A power transmission network is supervised and monitored as system disturbances within the network can result in partial compromise or even partial failure of the network. An operator is made aware of any outages within the network such as generator, substation or transmission line outages in order to conduct responsive measures. Therefore, the network is supervised at least partially by an operator. For human supervision, the state of the network is displayed on a screen or a similar viewing device such as a graphical user interface.
In general, the power transmission network includes a great number of data locations from which data values are collected. Stations used for supervision are known as supervisory control and data acquisition (SCADA) units. In these units, generally, some processes, parameters or local statuses are supervised automatically. In addition, human supervision is needed for proper operation of the network. However, the operator is physically not able to analyze every single data location and the data values received from it. Therefore, in order to be able to assess the network state, it is known to interpolate the data values of neighboring data locations and to visualize the original data and the interpolated values, for example, by means of areal color coding or shading, or by means of iso-lines or contour lines interconnecting locations of equal value on a map. However, the interpolation operation is a heavy calculation load for the system processor due to the great number of data locations and the correlation between those locations.
In the map, the geographical distribution of the data locations are shown in a graphical visualization, such as the above-mentioned color code, iso-lines, or a similar representation. The visualization highlights network problems and their location such as by coloring the respective area on the map. This allows the operator to assess the network state without analyzing each data location and allows the operator to take appropriate measures to resolve the problem.
U.S. Pat. No. 6,313,752 discloses a way of displaying dynamic on-line operating conditions of an interconnected power transmission network, and discloses a use of iso-voltage contours for visualization of power system operating conditions. A location and nature of any disturbance occurring in the network is indicated on the map by a change in the positions of the isovoltage and isophase contour lines relative to their normal positions.
However, as the system has to acquire, analyze and display a great amount of data values from many different data locations, the visualization update to represent the latest acquired data values is relatively slow, for example, in a large network, it can take up to several seconds to update the data and refresh the visualization display. Thus, the operator experiences a time delay while supervising the network as only a snapshot of the network state is displayed. The time delay is not only inconvenient for the operator but can delay time-critical measures and responses to problems while an emergency develops within the network as the operator is not updated in real-time.